Particles are small devices that can be attached to a person, an object or the environment. Particles contain wireless communication, computing power and memory, sensors and actuators. Particles can recognize their environment but also the state of the object they are attached to. They can are able to communicate context based. Particles communicate spontaneously peer-to-peer without supporting infrastructure. They can - nevertheless be connected to the internet via a XBridge.
Core of the system is the communication board (therefore often called Core Board). It consists of a RF transceiver circuit with a costumized radio protocol allowing it to communication with other particle computers in the environment, a microprocessor and a simple movement sensor. Different boards can be connected to the particle to transform it into a powerful sensor node. The standard setting (like in the above picture) - is a particle board stacked together with a simple sensor board.
What to do with such a Particle?
Particle computer follow the idea of post-hoc augmentation of every day objects. You can simply take a particle computer, attach it to an object and program your application (using standard ANSI C) on the particle or a wirelessly connected PC. A collection of development library, tools and basic applications like beacons or repeater are available as a free download. The standard program on a particle computer acts like sensor network node and will send you periodically a bunch of different sensor readings like acceleration, temperature, audio level, different light levels, movement as a basis for context recognition. With an XBridge infrastructure installed, you can watch incoming sensor or context values in real time like on an oszilloscope with the Particle Analyzer.
Development with particles
The development with particle computers is very easy. A lot of example programs are provided and there is a forum where all partners using the particle computers exchange their experience and newest code revisions. Particles have a elaborated library of drivers for different hardware extensions like sensors and actuators as well as a comfortable suite with a broad functionality for communication and configuration of particles. Furthermore, the particle computer can be programmed over-the-air. This means, you can leave the particle in it's application place (e.g. attached to an object somewhere in the room) and upload your lastest application code from your desk or even over the internet.
(left: sensor board stacked on a particle core board, middle: XBridge to connect particles to the internet, right: the particle analyzer: an over-the-air oszilloscope)
The particle computers are designed with the principle of modularity. This principle is followed in both the software and hardware architecture. All the different hardware components are interconnected through the same connector. Possible hardware extensions are cominations of different sensor boards, a selfttest board, serial usb and internet connectors, a generic board for hands-on development and experiments. More than one board can be stacked together at one time.
The software library follows the same modularity. You can simply include the
necessary drivers for your hardware components and then you get comfortable API
to read sensor values or communicate with other particle computers or
applications on your PC.
The infrastructure supports Smart-Its based applications and provide access for applications to Particle. These applications can run on large variety of computers as PCs or PDAs. Infrastructure is optional for the functionality of the Particle itself but may be required for certain services such as wireless development and maintenance of Particle applications. Infrastructure equipment is physically located nearby the place of Particle devices and enables access to Particle over the Internet and vice versa. They can also offer additional information as location information or a history database.
The above figure shows a
setting with several Smart-Its Particles distributed among rooms of an office environment. Particles can access the Internet by using
the XBridges infrastructure devices. These XBridges
are small device units that are connected to the Internet via an Ethernet plug
and connected to the Smart-Its Particle network via wireless radio frequency
(RF) transmission. For development and application software purposes, a ParticleDB
database service holds history information from all Smart-Its and their
communicated traffic for later debugging, maintaining or scripting. This database can
be queried either
via a Web-Interface or directly via SQL queries from applications.